JP2021085428A - Hose connection structure - Google Patents

Abstract

To provide a hose connection structure which is strong in a pullout force, and high in the reliability of seal performance.SOLUTION: A connection member 1 and a cylinder part 10 are inserted into a flexible hose 2, and connected to each other. The flexible hose 2 has a resin-made inner layer 21 having a substantially-smooth internal peripheral face, and a reinforcing layer 22 including a reinforcing fiber body which is laminated on the outside of the inner layer. A first cylinder part 11 and a second cylinder part 12 located at a depth side of the hose rather than the first cylinder part 11 are arranged at the cylinder part 10. A plurality of annular protrusions 11a exerting in a substantially-triangular cross section shape is aligned at an external periphery of the first cylinder part 11, and a portion between the adjacent annular protrusions 11a is set as a first annular groove 11g. A plurality of cylindrical flat faces 12p and a second annular groove 12g located between the adjacent flat faces are formed at an external periphery of the second cylinder part 12. The second annular groove 12g is shallow in a groove depth compared with that of the first annular groove 11g, and in a position corresponding to both the first cylinder part 11 and the second cylinder part 12, the external peripheral face of the flexible hose 2 is fastened.SELECTED DRAWING: Figure 1

Description

The present invention relates to a flexible hose connection structure. In particular, the present invention relates to a hose connection structure in which a tubular portion of a connecting member is inserted inside a flexible hose to connect the two.

When connecting a flexible hose to a connecting member, a technique of inserting a tubular portion of the connecting member inside the flexible hose and connecting the two is widely used. In particular, the inserted tubular portion is a so-called bamboo shoot. There is known a connection structure that is formed in a shape to prevent the hose from coming off, improve the sealing property, and improve the insertion workability.

For example, in relation to the hose connection structure using the bamboo-shaped tubular portion described above, Patent Document 1 describes a hose connection in which the radius of curvature of the radius applied to the bottom of the annular groove is increased toward the root side of the tubular portion. The technique of the member is disclosed, and the hose connecting member discloses that the stress concentration in the annular groove is relaxed and a hose connecting member having a greater strength against a lateral force can be obtained.

JP-A-2018-155296

When connecting a flexible hose to a connecting member having such a bamboo shoot-shaped tubular portion, the outer peripheral portion of the flexible hose is attached in order to prevent the hose from coming off or to improve the sealing property of the connecting portion. Complete the hose connection by tightening with a sleeve or band.

However, when the flexible hose has a reinforcing layer containing reinforcing fibers such as reinforcing threads, the sealing property of the connecting portion is insufficient even though the outer circumference of the flexible hose is firmly tightened with a sleeve or the like. It turned out that it could happen.

An object of the present invention is to provide a hose connection structure for a flexible hose having high pull-out force and high reliability of sealing property.

The inventors have investigated why the sealing property is insufficient when connecting a flexible hose to a connecting member having a bamboo shoot-shaped tubular portion, even though the hose is tightly tightened. As a result of diligent examination, when the hose is tightened, the top of the bamboo-shaped annular protrusion may bite into the inner peripheral surface of the hose and damage the inner circumference of the hose. When it reached, the inventors found that the air and liquid inside the hose traveled along the reinforcing thread, reached the end of the hose and leaked, and the sealing property of the hose was impaired.

The inventors further studied and found that the above problem can be solved by forming the tubular portion of the connecting member inserted into the hose into a configuration in which two tubular portions having different outer peripheral surface shapes are combined in a specific order. And completed the present invention.

The present invention has a hose connection structure in which a tubular portion of a connecting member is inserted inside a flexible hose to connect the flexible hose and the connecting member, and the flexible hose has a substantially smooth inner circumference. A flexible hose having a laminated structure having a resin inner layer having a surface and a reinforcing layer including a reinforcing fiber body laminated on the outer side of the inner layer. A second cylinder portion located on the back side of the hose from the first cylinder portion is provided, and a plurality of annular protrusions having a substantially triangular cross-sectional shape are arranged in a row on the outer circumference of the first cylinder portion. The portion between the adjacent annular protrusions is the first annular groove, and the outer periphery of the second tubular portion has a plurality of cylindrical flat surfaces and a second annular groove located between the adjacent flat surfaces. A groove is formed, and the second annular groove has a shallower groove than the first annular groove, and is flexible at a position corresponding to both the first cylinder portion and the second cylinder portion. It is a hose connection structure in which the outer peripheral surface of the hose is tightened and the hose is fixed to the cylinder portion of the connecting member (first invention).

In the first invention, preferably, the width of the second annular groove is narrower than that of the first annular groove (second invention). Further, in the second invention, preferably, the top of the annular protrusion of the first cylinder portion and the flat surface of the second cylinder portion have substantially the same diameter (third invention). Further, in the third invention, preferably, the width L1 of the flat surface of the second cylinder portion and the width L2 of the second annular groove of the second cylinder portion are 0.7 ≦ L1 / L2 ≦ 3. (Fourth invention).

According to the hose connection structure (first invention) of the present invention, a hose connection structure having high pull-out force and high reliability of sealing property can be obtained.

Further, if the second invention and the fourth invention are performed, the reliability of the sealing property is further enhanced. Further, according to the third invention, both the pull-out force and the reliability of the sealing property are further enhanced.

It is a partial cross-sectional view which shows the structure of the connection member used in the hose connection structure of 1st Embodiment. It is an enlarged sectional view of the part A of FIG. It is a partial cross-sectional view which shows the structure of the flexible hose which can be used for the hose connection structure of 1st Embodiment. It is a figure which shows a part of the process of connecting a connecting member and a flexible hose schematically. FIG. 5 is an enlarged cross-sectional view showing the structure of a connecting member of another embodiment used for a hose connecting structure. FIG. 5 is an enlarged cross-sectional view showing the structure of a connecting member of still another embodiment used for a hose connecting structure.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, exemplifying a hose connection structure for connecting a pressure-resistant industrial hose to a connecting member. The invention is not limited to the individual embodiments shown below, and the embodiments can be modified and implemented. In the hose connection structure according to the embodiment of the invention, as shown in FIG. 4, the tubular portion 10 of the connecting member 1 is inserted inside the flexible hose 2, and the outer circumference of the hose is tightened by the sleeve 3. The flexible hose 2 and the connecting member 1 are connected.

FIG. 1 is a partial cross-sectional view showing the structure of the connecting member 1 used in the hose connecting structure of the first embodiment. In FIG. 1, the upper half of the central axis m is shown in a cross-sectional view, and the lower half is shown in an external view. The connecting member 1 is a tubular member formed in a hollow cylindrical shape, and has a tubular portion 10 inserted inside a flexible hose and a connecting portion 15 to be connected to another member.

The connecting member 1 is made of a metal material (brass, cast iron, stainless steel, etc.), a hard synthetic resin material, or the like, and is manufactured by a known manufacturing method according to the material and shape. Further, the connecting portion 15 of the connecting member 1 may have a shape that can be connected to another member (such as a mating member of the connecting structure), and the specific form and configuration thereof are not particularly limited. In the connection member 1 of the present embodiment, the connection portion 15 is formed in a flange shape with an enlarged diameter at the end portion of the pipe, and such a connection portion has a known connection structure commonly referred to as a victic type or the like. It can be connected to other connecting members.

The tubular portion 10 of the connecting member 1 will be described in detail. The tubular portion 10 is provided with a first tubular portion 11 and a second tubular portion 12. The tubular portions 11 and 12 are cylindrical, respectively, and are provided side by side in the axial direction of the tubular portions. The second tubular portion 12 is provided so as to be located on the inner side of the hose, that is, on the tip end side (right side in FIG. 1) of the tubular portion 10 with respect to the first tubular portion 11. The first tubular portion 11 and the second tubular portion 12 have different outer peripheral surface shapes.

A plurality of annular protrusions 11a and 11a having a substantially triangular cross-sectional shape are arranged in a row on the outer circumference of the first tubular portion 11. That is, the annular protrusions 11a and 11a are formed in a triangular shape, that is, a ring shape so that the top portion 11t of the annular protrusion is located on the outermost circumference of the cylinder in the cross section shown in the enlarged cross-sectional view of FIG. The top of the annular protrusion may be rounded or chamfered. A plurality of annular protrusions 11a and 11a are provided side by side in the axial direction. The number of annular protrusions is preferably 3 or more and 15 or less, and more preferably 5 or more and 10 or less. The portions between the adjacent annular protrusions 11a and 11a are annular grooves 11g and 11g. The annular groove of the first tubular portion 11 is referred to as the first annular groove 11g. The cross-sectional shape of the first annular groove 11g may be a substantially triangular shape as in the present embodiment, but may be another form.

A plurality of cylindrical flat surfaces 12p and 12p and second annular grooves 12g and 12g located between adjacent flat surfaces are formed on the outer periphery of the second tubular portion 12. Each flat surface 12p is formed in an annular shape substantially parallel to the axis m of the tubular portion 10. The width of the flat surface 12p is preferably 2 mm or more and 8 mm or less, and more preferably 3 mm or more and 6 mm or less. The width of the annular groove 12 g is preferably 1 mm or more and 6 mm or less, and more preferably 2 mm or more and 5 mm or less.

The groove of the second annular groove 12g is shallower than that of the first annular groove 11g. That is, the depth D2 of the second annular groove 12g is smaller than the depth D1 of the first annular groove 11g (that is, D1> D2) as measured in the radial direction of the tubular portion 10.

The flexible hose 2 is a flexible hose having a laminated structure having an inner layer 21 and a reinforcing layer 22. The inner layer 21 is a resin layer and has a substantially smooth inner peripheral surface exposed inside the hose 2. Examples of the resin constituting the inner layer include thermoplastic resins such as vinyl chloride resin and rubber, but the resin is not particularly limited. The smoothness of the inner peripheral surface may be such that the sealing property can be ensured by contacting and adhering to the outer peripheral surface of the tubular portion 10 of the connecting member 1.

The reinforcing layer 22 contains a reinforcing fiber body. Examples of the reinforcing fiber body include bundles of fibers composed of reinforcing fibers such as aramid fibers, glass fibers, carbon fibers, and metal fibers, yarns, strands, twisted yarns, and strings. In the reinforcing layer 22, these reinforcing fibers are embedded in the hose wall so as to form a cylindrical layer. The form in which the reinforcing fiber body is provided in the cylindrical layer is not particularly limited, but for example, a linear shape, a spiral shape, a spiral shape that intersects each other, a blade knitting shape, a woven cloth shape, a tubular woven cloth shape, a knit knitting shape, etc. The form of is exemplified.

The reinforcing layer 22 is laminated on the outside of the inner layer 21. Another layer may be provided between the inner layer 21 and the reinforcing layer 22. Further, although not essential, the flexible hose 2 may be provided with an outer layer 23 made of a soft synthetic resin on the outside of the reinforcing layer 22. Further, although not essential, the flexible hose 2 may be provided with a spiral reinforcing body 24 made of a metal wire or a hard resin wire. The spiral reinforcing body 24 may be integrated with the outer peripheral surface of the hose wall, or may be embedded inside the hose wall.

In the present embodiment, a reinforcing layer 22 provided in a spiral shape in which reinforcing fiber bodies made of aramid fibers intersect with each other is provided on the outer periphery of the inner layer 21 made of synthetic rubber, and soft chloride is further provided on the outer periphery of the reinforcing layer 22. An outer layer 23 made of vinyl resin is provided, and a spiral reinforcing body 24 made of hard vinyl chloride resin is embedded in the outer layer 23. The inner layer 21, the reinforcing layer 22, the outer layer 23, and the reinforcing body 24 are integrated with each other to form the flexible hose 2.

FIG. 4 schematically shows a step of connecting the connection member 1 and the flexible hose 2 described above. The tubular portion 10 of the connecting member 1 is inserted inside the flexible hose 2. The insertion is performed so that both the first cylinder portion 11 and the second cylinder portion 12 are covered with the flexible hose 2.

With the tubular portion 10 inserted inside the flexible hose, the flexible hose 2 is tightened from the outside of the flexible hose 2, and the connection between the connecting member 1 and the flexible hose 2 is completed. Regarding the axial position of the tubular portion 10, the outer peripheral surface of the flexible hose is tightened at a position corresponding to both the first tubular portion 11 and the second tubular portion 12, and the hose 2 is the tubular portion of the connecting member 1. It is fixed at 10. By such tightening, the outer peripheral surface of the hose 10 and the inner peripheral surface of the hose 2 so that the inner peripheral surface of the hose bites into the first annular grooves 11g and 11g and the second annular grooves 12g and 12g of the tubular portion 10. Is in close contact with each other, and the hose 2 and the cylinder portion 10 are connected.

The tightening means is not particularly limited, and examples thereof include a metal sleeve, a tightening band, and a tightening member divided into a plurality of members in the circumferential direction. In the present embodiment, an aluminum alloy sleeve 3 provided at a length and position that covers the entire portion corresponding to the first cylinder portion 11 and the second cylinder portion 12 is provided on the outer circumference of the flexible hose 2 and is engaged. The flexible hose is tightened by plastically deforming the sleeve 3 by caulking so that the sleeve 3 contracts. When a known tightening band is used for tightening, tightening may be performed using two tightening bands so as to correspond to each of the first cylinder portion 11 and the second cylinder portion 12.

The operation and effect of the hose connection structure of the first embodiment will be described. According to the hose connection structure, the pulling force is enhanced and the reliability of the sealing property is enhanced.

A plurality of annular protrusions 11a, 11a having a substantially triangular cross-sectional shape are arranged in a row on the first tubular portion 11, which contributes to the improvement of the pull-out force. This is because the top portion 11t of the annular protrusion 11a bites into the inner peripheral surface of the inner layer 21 of the flexible hose 2. In the prior art, the inventors have found that such biting causes deterioration of the sealing property, but as will be described later, in the hose connection structure of the above embodiment, the first cylinder portion and the second cylinder portion are combined. As a result, even if the top portion 11t of the annular protrusion 11a in the first tubular portion 11 bites into the inner circumference of the hose wall and the inner peripheral surface of the hose is damaged, the sealing property does not deteriorate.

A plurality of cylindrical flat surfaces 12p and 12p and second annular grooves 12g and 12g located between adjacent flat surfaces are formed on the outer periphery of the second tubular portion 12, and the first annular groove portion 12 is formed. The depth of the groove in the second annular groove 12g is shallower (D1> D2) than in the groove 11g, which contributes to the improvement of the sealing property.

When the hose 2 is tightened and the hose wall is pressed against the outer periphery of the second tubular portion 12, the flat surface 12p of the second tubular portion 12 and the inner peripheral surface of the hose are in close contact with each other in an annular shape and sealed. Further, the inner circumference of the hose wall is pushed into the second annular groove 12g, and the hose inner peripheral surface and the second cylinder portion are more strongly adhered to each other at the edge portion of the boundary between the flat surface 12p and the second annular groove 12g. The seal will be more secure.

The second annular groove 12g of the second tubular portion 12 has a shallower groove depth than the first annular groove 11g of the first tubular portion 11, so that the second annular groove 12g Deformation of the hose wall at the portion of the hose is suppressed, and damage reaching the reinforcing layer 22 is less likely to occur in the inner layer 21 of the hose at the portion of the second annular groove 12g. This enhances the reliability of the sealing property.

In the hose connection structure, the second cylinder portion 12 is provided so as to be located on the back side of the hose from the first cylinder portion 11, that is, on the tip side of the cylinder portion 10, so that the first cylinder portion is tentatively provided. Even if the top portion 11t of the annular protrusion 11a bites into the inner peripheral surface of the hose and is damaged, the damage does not adversely affect the sealing property. Since the second cylinder 12 is closer to the inside of the hose than the first cylinder 11, the seal is perfect regardless of the condition of the first cylinder as long as the seal in the second cylinder 12 is ensured. This is because it becomes something like that.

As described above, according to the hose connection structure of the above embodiment, the annular groove 12g is relatively shallow, and the portion of the second tubular portion 12 having the flat portion 12p that does not easily damage the inner peripheral surface of the hose is firmly reliable in sealing property. Since it is possible to firmly prevent the hose from coming off at the portion of the first tubular portion 11 having the annular protrusion 11a having a substantially triangular cross section while improving the property, both the pulling force of the hose connection and the reliability of the seal can be improved.

From the viewpoint of further enhancing the reliability of the sealing property, the groove depth D2 of the second annular groove 12g of the second tubular portion 12 is set with respect to the groove depth D1 of the first annular groove 11g of the first tubular portion 11. D2 / D1 ≦ 0.7 is preferable, and D2 / D1 ≦ 0.5 is more preferable.

Further, from the viewpoint of further enhancing the reliability of the sealing property, it is preferable that the width of the second annular groove 12g is narrower than that of the first annular groove 11g. That is, it is preferable that the width L2 of the second annular groove 12g in the tubular portion axis direction is L3> L2 with respect to the width L3 of the first annular groove 11g in the tubular portion axial direction. The narrower the width L2 of the second annular groove 12g, the more difficult it is for the inner peripheral surface of the hose wall to enter the second annular groove 12g, and it is more certain that the inner peripheral surface of the hose is damaged at the second tubular portion 12. It is prevented and the reliability of the sealing property is further improved. From the viewpoint of improving the sealing property, L2 / L3 ≦ 0.7 is more preferable, and L2 / L3 ≦ 0.5 is particularly preferable.

Further, from the viewpoint of further improving the reliability of the pull-out force and the sealing property, the top portion 11t of the annular protrusion 11a of the first cylinder portion 11 and the flat surface 12p of the second cylinder portion 12 have substantially the same diameter. That is, it is preferable that both are arranged on substantially the same virtual cylinder. With this configuration, the hose wall is sufficiently tightened in the second cylinder portion 12, the flat surface 12p is in close contact with the hose wall, sufficient and reliable sealing performance is exhibited, and the hose wall is exhibited in the first cylinder portion 11. The top 11t of the annular protrusion 11a firmly bites into the hose, and the pulling force of the hose connection is further enhanced.

Further, from the viewpoint of further improving the reliability of the sealing property, the width L1 of the flat surface 12p of the second cylinder portion 12 and the width L2 of the second annular groove 12g of the second cylinder portion are 0.7 ≦ L1 / L2. It is preferable that ≦ 3. If the ratio of the width of the flat surface 12p to the width of the annular groove 12g is set, it is possible to prevent the inner peripheral surface of the hose from excessively entering the second annular groove 12g and damaging the inner circumference of the hose. Is.

Further, from the viewpoint of further increasing the pull-out force, in the annular protrusions 11a and 11a of the first tubular portion 11, the annular protrusions 11a are located on the hose back side (right side in FIG. 2) and the outer peripheral surface P1 and the hose end side (FIG. 2). It has an outer peripheral surface P2 located on the left side of 2), and the angle formed by the outer peripheral surface P1 located on the back side of the hose with the central axis m of the cylinder portion is larger than the outer peripheral surface P2 located on the end side of the hose. Is preferably made smaller. With such a configuration, the first cylinder portion 11 has a shape to prevent it from coming off like a saw blade, and the pulling force of the hose connection is particularly enhanced.

Further, although not essential, in the second annular grooves 12g and 12g of the second tubular portion 12, the surface P22 located on the back side of the hose (right side in FIG. 2) is the hose in each of the annular grooves 12g. It is preferable that the angle formed with the central axis m of the tubular portion is larger than that of the surface P21 located on the end side (left side in FIG. 2). With such a configuration, each of the second annular grooves 12g of the second tubular portion 12 has a retaining shape, and the pulling force of the hose connection is particularly enhanced.

The invention is not limited to the above embodiment, and can be implemented with various modifications. Other embodiments of the invention will be described below, but in the following description, parts different from the above-described embodiments will be mainly described, and detailed description of similar parts will be omitted. Moreover, these embodiments can be carried out by combining some of them with each other or replacing some of them.

5 and 6 show a modified example of the tubular portion 10 in the above embodiment.
In the tubular portion 30 according to the second embodiment shown in FIG. 5, the width L3 of the first annular groove 31 g of the first tubular portion 31 is substantially the width L2 of the second annular groove 32 g of the second tubular portion 32. It is said to be the same width. Even in such a form, the reliability of the sealing property can be improved by the second cylinder portion 32 while improving the pulling force by the first cylinder portion 31.

In the cylindrical portion 40 according to the third embodiment shown in FIG. 6, the cylindrical flat surface 42p of the second tubular portion 42 is located inside the cylindrical portion in the radial direction with respect to the top portion 41t of the annular protrusion 41a of the first tubular portion 41. It is designed to be placed. That is, the radius of the virtual cylinder in which the top 41t is arranged is R1, the radius of the virtual cylinder in which the flat surface 42p is arranged is R2, and R1> R2. According to such a configuration, it is possible to reduce the insertion resistance when inserting the tubular portion 40 of the connecting member into the flexible hose while increasing the pulling force of the hose connecting structure and improving the reliability of the sealing property, and the connection can be made. The work can be done more efficiently.

Further, in the second annular groove 42g provided in the second tubular portion 42 like the tubular portion 40 in the third embodiment, the surface on the back side of the hose and the surface on the end side of the hose are relative to the central axis of the tubular portion. , It may be provided so as to have a symmetrical shape with respect to the radial direction of the tubular portion so as to have the same inclination angle. With the form of the second annular groove 42g, the edge between the annular groove 42g and the flat surface 42p is evenly obtuse, and the hose inner circumference is more reliably prevented from being damaged by the edge when tightened. The reliability of the sealing property is further improved.

The flexible hose is a flexible hose having a laminated structure having a resin inner layer 21 having a substantially smooth inner peripheral surface and a reinforcing layer 22 including a reinforcing fiber body laminated on the outer side of the inner layer. , Not particularly limited. The specific material constituting the hose can also be selected from known hose materials. Further, the specific use of the hose is not particularly limited. Examples of hoses include hoses that send gas and liquid, hoses that send refrigerants, slurry and concrete, hoses that send powder and granules, and hoses that transmit pressure of gas and liquid.

The specific shape of the connecting portion 15 of the connecting member 1 is arbitrary. The connecting portion 15 of the connecting member 1 may be connected to another member or another connecting member by welding or the like.
Further, the connecting member does not have to be an independent member, and may be integrally formed at a portion for connecting the hose to a specific device. For example, when a tubular body for connecting a hose is provided at the slurry delivery port of the slurry pumping device, the tubular body portion is regarded as a connecting member in the above embodiment, and the tubular body portion 10 in the above embodiment is regarded as the connecting member in the above embodiment. A portion corresponding to may be provided.

(Example)
A flexible hose 2 having an inner diameter of 75 mm corresponding to the first embodiment was prepared.
The connecting member 1 corresponding to the first embodiment was prepared. The material of the connecting member is stainless steel. The outer diameters of the first cylinder and the second cylinder are 75.8 mm, and the first cylinder 11 has nine triangular cross sections so that the depth of the first annular groove is 1 mm and the width of the groove is 5 mm. The annular protrusions of the above were arranged in a row. Further, in the second tubular portion 12, three cylindrical flat portions having a width of 4 mm are provided so that the depth of the second annular groove is 0.5 mm and the width of the groove is 3 mm.
The tubular portion 10 of the connecting member 1 is inserted inside the flexible hose 2, and is made of an aluminum alloy having a thickness of 3 mm so as to cover both the hose outer peripheral surface of the portion corresponding to the first tubular portion and the second tubular portion. The sleeve was put on the outer circumference of the flexible hose 2 and crimped so as to tighten the hose, and the hose 2 and the tubular portion of the connecting member were joined. As described above, the hose connection structure of the example was obtained.

A hose connection structure of a comparative example similar to that of the example was obtained except that the shape of the tubular portion was different. In the comparative example, 14 annular protrusions having a triangular cross section were arranged in a row on the tubular portion of the connecting member so that the depth was 1 mm and the width of the groove was 5 mm, similarly to the first annular groove. That is, in the comparative example, the same annular protrusion and annular groove as the first tubular portion are provided in the portion that was designated as the second tubular portion in the embodiment.

The hose connection structures of Examples and Comparative Examples were subjected to pressure resistance and leakage tests, respectively.
In the test, a connecting member 1 is connected to both ends of a flexible hose 2 cut to a length of 1 m, an iron plate having a thickness of 15 mm is welded to the connecting portion of the connecting member 1, and a water pressure is applied to the inside of the hose. It was.
The test was carried out by gradually increasing the water pressure until the hose was disconnected from the connecting member or the hose was broken.

In the hose connection structure of the embodiment, water leakage and hose disconnection did not occur even if the water pressure was increased. In the hose connection structure of the embodiment, the hose itself broke when the water pressure finally reached 4.0 MPa.

On the other hand, in the hose connection structure of the comparative example, water leakage from the hose end occurred along the reinforcing fiber body at a water pressure of 3.0 MPa. When the water pressure was further increased in the hose connection structure of the comparative example, pinhole fracture occurred in the hose wall at 3.2 MPa. It is presumed that water reached the reinforcing layer including the reinforcing fiber from the damaged part of the inner layer, and water entered between the reinforcing layer and the outer layer, which led to the destruction of the pinhole.

In the hose connection structure of the comparative example, no improvement was observed in the sealing property of the connection structure even if the degree of caulking was increased. With the hose connection structure of the comparative example, it was not possible to improve both the pull-out force and the reliability of the sealing property.

The hose connection structure allows a tubular connecting member to be connected to the end of the flexible hose, and has high industrial utility value.

1 Connecting member 10 Cylindrical portion 11 1st tubular portion 11a annular protrusion 11g 1st annular groove 12 2nd tubular portion 12p Cylindrical flat surface 12g 2nd annular groove 2 Flexible hose 21 Inner layer 22 Reinforcing layer 23 Outer layer 24 Spiral reinforcement 3 sleeve

Claims (4)

A hose connection structure in which a tubular portion of a connecting member is inserted inside the flexible hose to connect the flexible hose and the connecting member.
The flexible hose is a flexible hose having a laminated structure having a resin inner layer having a substantially smooth inner peripheral surface and a reinforcing layer including a reinforcing fiber body laminated on the outer side of the inner layer.
The tubular portion is provided with a first tubular portion and a second tubular portion located on the back side of the hose from the first tubular portion.
A plurality of annular protrusions having a substantially triangular cross-sectional shape are arranged in a row on the outer circumference of the first tubular portion, and the portion between the adjacent annular protrusions is the first annular groove.
A plurality of cylindrical flat surfaces and a second annular groove located between adjacent flat surfaces are formed on the outer circumference of the second tubular portion.
Compared to the first annular groove, the second annular groove has a shallower groove.
The outer peripheral surface of the flexible hose is tightened at a position corresponding to both the first cylinder portion and the second cylinder portion, and the hose is fixed to the cylinder portion of the connecting member.
Hose connection structure. The width of the second annular groove is narrower than that of the first annular groove.
The hose connection structure according to claim 1. The top of the annular protrusion of the first cylinder and the flat surface of the second cylinder have substantially the same diameter.
The hose connection structure according to claim 2. The width L1 of the flat surface of the second cylinder portion and the width L2 of the second annular groove of the second cylinder portion are set to 0.7 ≦ L1 / L2 ≦ 3.
The hose connection structure according to claim 3.

Images